To demonstrate best practice, we recommend you create and follow a biofouling management plan and record your maintenance activities in a log book.

If your vessel has been stationary for periods of time, it probably requires cleaning before arrival in New Zealand. Evidence of cleaning needs to be kept and may be requested by a quarantine inspector on arrival.

Requirements depend on time in New Zealand

Most work vessels fall under MPI’s 'long-stay' category (plan to be in New Zealand for 21 days or more or visiting places that aren't places of first arrival).

Long-stay vessels are only allowed a slime layer and gooseneck barnacles.

Short-stay vessels (20 days or less) are allowed slightly more biofouling.

Allowable amounts of biofouling are set out in the biofouling craft risk management standard.

Photos to help you assess biofouling

Species such as acorn barnacles (A) and bryozoans (B) are not allowed. (Photos: John A Lewis)

Biofouling levels over the allowed threshold. (Photos: John A Lewis)

Clean before you leave

Operators of vessels that are more likely to be fouled must provide MPI with evidence, before they arrive, that the vessel will be clean.

You'll need to arrange a biofouling inspection by an appropriately qualified provider and provide the evidence to MPI before leaving for New Zealand. Evidence may include provider recommendations and evidence of cleaning or treatment of the hull and niche areas.

You may get the vessel cleaned or treated in New Zealand within 24 hours of arrival if you can provide proof with your arrival documents of a facility booking.

Cleaning means the removal of all biofouling (other than a slime layer and gooseneck barnacles) from all hull and niche areas.

Hull appendages as niches

Any hull appendages can act as niche areas, even when painted with effective antifouling. You may need to include them in a maintenance programme. Hull appendages include:

dry docking support strips

bow and stern thrusters

bilge keels, cooling scoops and propulsion scoops

rudder hinges and stabiliser fin apertures.

Hull appendages that can't be painted with antifouling paint – because it affects their operation – may need additional maintenence and cleaning. These include:

anodes

velocity probes

echo sounders.

Internal seawater systems

Effective marine growth protection systems (MGPS) can be fitted to internal seawater systems prone to biofouling. Use these systems regularly and monitor them to make sure they're working well. If MGPS haven't been fitted or haven't prevented biofouling, treat internal systems before arriving in New Zealand.